The long-term goal of this research project is to understand how differentially-expressed trans-acting factors in neurons can control pre-mRNA processing to precisely regulate neuronal gene expression. The powerful genetics, molecular biology and transgenic techniques of Drosophila, along with the emergent DNA microarray technology, will be utilized to study the role of ELAV in mRNA processing and its overall impact on gene expression in neurons. ELAV is the founding member of the ELAV/Hu family of RNA-binding proteins, which is conserved in both vertebrates and invertebrates. Members of the ELAV/Hu family serve diverse roles in mRNA processing, including splicing, stability and translatability. The aims of the project are: (1) elucidation of mechanisms of ELAV's interactions with RNA transcripts, (2) identification of direct targets of ELAV using immunoprecipitated ELAV-ribnucleoprotein complexes and DNA microarrays, (3) assessment of the overall impact of ELAV on gene expression using microarray technology. Together, these approaches will begin to identify networks of genes that are regulated collectively and provide a comprehensive view of how post-transcriptional regulation is utilized in neuronal gene expression. Given the evolutionary conservation between Drosophila and human genomes, insights in regulatory strategies will be directly transferable to human studies. Human members of the ELAV/Hu family have been implicated in pathogenesis of paraneoplastic cerebellar dysfunction. RNA processing defects have been documented in a large number of human diseases and inherited disorders including cancer, muscular dystrophy and fragile X syndrome.